import java.sql.*;

public class hello {
    public static void main(String[] args){

        Connection connection =null;
        PreparedStatement preparedStatement =null;
        ResultSet resultSet =null;


        //jdbc
        //1 加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");

            //2 创建连接
            String url="jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";

             connection = DriverManager.getConnection(url, "root", "Ddj0302.");

            if(connection!=null){
                System.out.println("连接成功");
            }

            //3.写sql
            String sql="select*from user";

            //4.预编译sql

             preparedStatement = connection.prepareStatement(sql);

            //5 执行sql
             resultSet = preparedStatement.executeQuery();

            //6.遍历结果
            while (resultSet.next()){
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id+"----"+name+"----"+pass);

            }

        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {
                if(resultSet!=null){

                    resultSet.close();
                }
                 if (preparedStatement!=null){
                     preparedStatement.close();
                 }
                if (connection!=null) {

                    connection.close();
                }

            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
}
